The class of polymers of carbon monoxide and olefin(s) has been known in the art for some time. Brubaker, U.S. Pat. No. 2,495,286, produced such polymers of relatively low carbon monoxide content in the presence of free radical initiators, e.g., peroxy compounds. U.K. No. 1,081,304 produced similar polymers of higher carbon monoxide content in the presence of alkyl phosphine complexes of palladium as catalyst. Nozaki extended the reaction to produce linear alternating polymers in the presence of arylphosphine complexes of palladium moieties and certain inert solvents. See U.S. Pat. No. 3,694,412, for example.
The linear alternating polymers have been shown to be of the general repeating formula -CO-A- wherein A is the moiety of ethylenically unsaturated hydrocarbon. By way of specific illustration, when the polymer is a copolymer of carbon monoxide and ethylene, the copolymer will be of the repeating formula -CO-CH.sub.2 --CH.sub.2).
More recently, the class of linear alternating polymers, now becoming known as polyketones or polyketone polymers, has become of greater interest because of the greater availability of the polymers. Many of the more recent processes for the production of the linear alternating polymers are illustrated by a number of published European Patent Application Nos. including 121,965, 181,014, 213,671 and 257,633. Such processes involve the use of a catalyst composition formed from a salt of a Group VIII metal selected from palladium, cobalt or nickel, the anion of a non-hydrohalogenic acid having a pKa below about 6 and a bidentate ligand of phosphorus, arsenic or antimony. The scope of the polymerization process is extensive but, without wishing to be limited, a preferred catalyst composition is formed from a palladium carboxylate, especially palladium acetate, the anion of a non-hydrohalogenic acid having a pKa below 2 and a bidentate ligand of phosphorus. For some particular applications it has been found useful to employ other bidentate ligands. For example, in U.S. Pat. No. 4,788,279 there is disclosed a process for producing a copolymer of carbon monoxide and styrene which employs a nitrogen bidentate ligand of the formula ##STR1## wherein X and Y are the same or different organic bridging groups containing 3 or 4 atoms in the bridge at least 2 of which are carbon atoms. The compound 2,2'-bipyridine is an example of such a ligand. In copending U.S. patent application Ser. No. 140,013, filed Dec. 12, 1987 and Ser. No. 350,828, filed May 12, 1989 there are disclosed catalyst compositions useful for the production of polyketone polymers which are formed from, inter alia, sulfur- or selenium-containing bidentate ligands. It would be of advantage, however, to provide additional processes and additional catalyst compositions useful for the production of linear alternating polymers of carbon monoxide and ethylenically unsaturated hydrocarbons.